Roller extension slide

ABSTRACT

A roller extension slide including first and second track beams, a center beam of box section with wheels projecting through clearance openings of lateral webs engaging track surfaces of the track beams; guide flanges of the center beam engaging guide slots of the track beams for maintaining the track beams closely spaced; and the travel slot formed in each track beam. Center wheel axle extensions engage opposite ends of travel slots in the track beams for limiting the travel between retracted and extended positions of the track beams, with track beam wheel engagement spacing being at least 80% of the track length the first position and at least 40% in the second position, an extension distance being at least 80% percent of the track length, the first position being with the apparatus substantially contained within the track length. Also disclosed is a table incorporating a pair of the extension slides.

BACKGROUND

The present invention relates to extension slides, and more particularly to roller slides for leafed tables and the like having end portions that are adjacent in one position and spaced apart in another position for receiving one or more leaves whereby the table is made longer.

Table extension slides incorporating rollers are well known, being disclosed, for example, in U.S. Pat. No. 1,396,036 to Galerkin, U.S. Pat. Nos. 3,078,130, 3,078,131, and 3,169,806 to Beek, and U.S. Pat. No. 3,099,232 to Cooper. The Galerkin patent discloses a slide having an odd number of bars and a rack and pinion centering mechanism for symmetrical movement of the outside bars relative the the central bar. T-slots are formed in adjacent faces of the bars, with a plurality of wheels supported on blocks that engage one of the T-slots and having rolling engagement with the T-slot of the facing bar. The various configurations disclosed in the Breek patents each comprise first, second, and third lateral wooden beams having imbedded metallic tracks and an arrangement of wheels rotatably supported within tracks of the second and third beams and having rolling engagement with respective tracks of the first and second beams. The Cooper patent discloses a table slide assembly having telescoping members, one of the members carrying a wheel for supporting leaves of the table that are used with the table in its extended condition.

Table slides of the prior art typically exhibit one or more of the following disadvantages:

1. They are difficult to use in that they have excessive friction;

2. They are ineffective in that they are prone to excessive sagging and distortion during extension and retraction due to wide lateral spacing load-carrying components generally and of rollers in particular as well as poor structural integrity of cantilevered roller supports; and

3. They are expensive to manufacture in that they are excessively complicated, have excessively expensive components, and/or are difficult to assemble.

Thus there is a need for a roller table slide that overcomes at least some of the disadvantages of the prior art.

SUMMARY

The present invention meets this need by providing a roller extension slide assembly or apparatus that is particularly effective, inexpensive to produce, and easy to use. In one aspect of the invention, the apparatus includes elongate first and second track beams, each track beam having parallel-spaced facing track surfaces; an elongate center beam; a longitudinally spaced plurality of wheels rotatably mounted on the center beam for rolling engagement with the track surfaces of the first and second track beams; and structure for maintaining a parallel spaced relation of the track beams, wherein each of the track beams has track beam wheel engagement at a spacing of not less than 60 percent of a track length of that track beam in a first relative longitudinal position of the track beams and not less than 30 percent of the track length in a second position of the track beams, an extension distance between the first and second positions being not less than 80 percent of the track length. Preferably the apparatus includes structure for limiting travel of the rolling engagement, which can include a longitudinal travel slot formed in each track beam, and respective wheel axle extensions projecting from the center beam and engaging opposite ends of the travel slots in the extended and retracted conditions of the apparatus. The track beams and the center beam can be of equal length, the first relative position preferably being with the apparatus substantially contained within the track length.

The structure for maintaining the parallel spaced relation of the track beams can include each track beam having a longitudinal guide slot formed therein, and the center beam having a plurality of guide flanges for slidably engaging the guide slots of corresponding track beams. Preferably each of the guide flanges is one of an oppositely facing pair of flange portions, and the guide slot of each track member is one of a facing pair of guide slots for enhanced alignment of the track beams. Preferably the guide flanges engage the guide slots at locations spaced apart on each track beam not less than half of the corresponding track length for further enhanced alignment ans smoothness of the guiding. Preferably the center beam includes a main portion having a pair of parallel-spaced side webs connected by parallel-spaced lateral webs, the wheels being mounted between the side webs and projecting through clearance openings formed in the lateral webs, and the oppositely extending guide flanges forming coplanar extensions of the side webs for enhanced stiffness and structural integrity of the center beam.

Preferably each track beam includes a main portion of generally C-shaped cross-section including a pair of parallel-spaced track flanges forming the track surfaces, and a connecting web for enhanced strength and rigidity, and compactness of the apparatus. Each track beam can further include a mounting flange, the mounting flange preferably extending from the connecting web opposite one of the track flanges in generally coplanar relation thereto for further enhanced strength and rigidity of the track beam.

Preferably the apparatus further includes a longitudinally spaced plurality of axles mounted to the center beam, each axle supporting an independently rotatable pair of the wheels, each of the wheels being located between the track surfaces of a corresponding one of the track beams for facilitating smooth rolling engagement of the wheels with the track surfaces. Preferably the axles are mounted proximate opposite ends thereof to the center beam for enhanced rigidity in support of the wheels. Preferably at least some of the wheels have an outer resilient member for cushioned contact with the track surfaces of the track beam. The outer resilient member can be a rubber )-ring.

The apparatus of the present invention can be advantageously included in a table, with a first panel member being mounted to the first track beam and a second panel member mounted to the second track beam in coplanar relation to the first panel member and forming respective main table leafs, the leafs being in edgewise proximity in the first relative position of the track beams and being spaced apart in the second relative position of the track beams. The table can include a parallel spaced pair of the inventive apparatus correspondingly connected between the first and second panel members.

In another aspect of the present invention, the apparatus includes the first and second track beams, of generally C-shaped cross-section having the track flanges forming the track surfaces, and the connecting web; the center beam having the side webs and lateral webs; the wheels mounted between the side webs and projecting through clearance openings formed in the lateral webs for rolling engagement with the track surfaces; each track beam having the guide slot formed therein and the center beam having the guide flanges that slidably engage the guide slots for parallel-spaced maintenance of the track beams; and the travel slot formed in each track beam, with the wheel axle extensions projecting from the center beam and engaging opposite ends of the travel slots for limiting the travel between the first and second positions of the track beams, the track beam wheel engagement being not less than 80 percent of the track length the first position of the track beams and not less than 40 percent of the track length in the second position, the extension distance being not less than 80 percent of the track length, and the track beams and the center beam being of equal length, the first position being with the apparatus substantially contained within the track length.

DRAWINGS

These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description, appended claims, and accompanying drawings, where:

FIG. 1 is a fragmentary sectional bottom plan view of a roller slide according to the present invention, the slide being in a closed condition;

FIG. 2 is a fragmentary sectional side elevational view of the slide of FIG. 1;

FIG. 3 is an enlarged end elevational view of the slide of FIG. 1;

FIG. 4 is an enlarged sectional elevational view on line 4-4 of FIG. 1;

FIG. 5 is an enlarged sectional elevational view on line 5-5 of FIG. 1;

FIG. 6 is an enlarged sectional elevational view of a track beam of the slide on line 4-4 of FIG. 1;

FIG. 7 is a fragmentary sectional bottom plan view at reduced scale, showing the slide of FIG. 1 in an extended condition;

FIG. 8 is an elevational view of the slide of FIG. 1 in the extended condition of FIG. 7;

FIG. 9 is a bottom plan view showing a table incorporating a pair of slides as in FIG. 1, the table being in a closed condition;

FIG. 10 is a bottom plan view as in FIG. 9, the table being in an extended condition; and

FIG. 11 is an enlarged sectional elevational view as in FIG. 4, showing an alternative configuration of the slide.

DESCRIPTION

The present invention is directed to a roller extension slide that is particularly effective as a table extension slide. With reference to FIGS. 1-10 of the drawings, a roller slide assembly 10 includes a pair of track beams 12, a center beam 14, and a plurality of wheels 16 mounted to the center beam as described herein. Pairs of the wheels 16 are supported on respective axles 18 that are transversely mounted at linear parallel-spaced locations along the center beam 14. Each of the track beams 12 is formed having an elongate main portion 20 of generally C-shaped cross-section and a laterally extending mounting flange portion 22, one wheel 16 of each pair being positioned for rolling engagement with respective facing track surfaces 24 that are formed in respective laterally projecting track flanges 25 the main portion 20 over a full length of the track beam, the wheels being slightly smaller in diameter than a spacing between the track surfaces for free-rolling engagement. FIGS. 1 and 2 show the slide assembly 10 in a retracted condition; FIGS. 7 and 8 show the assembly in a fully extended condition.

An important feature of the present invention is that corresponding track surfaces 24 of the two track beams 12 are closely spaced laterally, the pairs of wheels 16 also being in adjacent relation on the axles 18. Consequently, load transmission between the track beams produces minimal twisting moment and deflection of the slide assembly 10 in the extended and retracted conditions as well as in intermediate positions.

As best shown in FIGS. 3, 4, and 6, the closely spaced alignment of the track beams 12 is maintained by the center beam 14 having pairs of guide flanges 26 that project into corresponding guide slots 28 that are formed in the track beams. The guide flanges 26 and the guide slots 28 are each formed uniformly for the full length of their respective members for smoothly maintaining the closely spaced alignment over the full travel distance between the retracted and extended conditions of the roller slide assembly 10. Also, the track beams and the center beam 14 are preferably configured for high strength and stiffness while exhibiting a compact cross-sectional profile. Thus, not only are the twisting moment and deflection minimized by the respective track surfaces 24 being closely spaced, the mounting flange portions 22 of the track beams 12 are relatively closely spaced as well, and the overall depth of the assembly 10 can be confined as appropriate for use as a table slide. This is achieved in the present invention by configuring both the track beams 12 and the center beam 14 for great strength and stiffness within the preferred compact cross-sectional profile. To this end the center beam 14 is tubular in form, having a pair of parallel-spaced planar side webs 30 that are orthogonally connected by a vertically spaced pair of lateral webs 32. Opposite ends of the axles 18 are mounted in the side webs 30 as further described below, thereby avoiding disadvantageous cantilevered mounting. Clearance openings 33 are formed in the lateral webs 32 for receiving the wheels 16, the wheels projecting through the openings for engagement with the track surfaces 24 of the track beams 12. The bending strength and stiffness of the center beam 14 is further enhanced by the guide flanges 26 being coplanar extensions of the side webs 30.

The strength and stiffness of the track beams 12 are similarly enhanced by concentrating material in upper and lower portions of the beams. More particularly, each beam main portion 19 has a facing pair of the guide slots 28 formed between a main web 34 and respective slot webs 36 that project toward each other from locations adjacent to the track surfaces 24, the slot webs materially contributing to the strength and stiffness of the track beam 12. Also, the main web 34 has a central thinned region 38 for clearing opposite ends of the axles 18, thereby allowing the guide flanges 26 and side webs 30 of the center beam 14 to be adjacent to outer portions of the main web 34, the thinned region 38 detracting minimally from the strength and stiffness of the track beam 12. Further, the mounting flange portions 22 contribute materially to the strength of the track beams, the mounting flange portions of each track beam 12 having a plurality of mounting holes 39 formed therein for connection of the slide assembly 10 to external members for extensible relative movement thereof as further described below.

As best shown in FIG. 4, the axles 18 of a preferred exemplary configuration of the roller slide 10 shown in the drawings (with one exception described below) are headed on opposite ends for axial retention between the side webs 30 of the center beam 14, one or both of the head formations being performed by riveting. As best shown in FIG. 5, a central axle, designated 18′, includes a headed shaft 40 that projects through one of the side webs 30 and into the opposite side web, and a cap screw 42 that threadingly engages the headed shaft. Headed portions of the shaft 40 and the cap screw 42 project into respective longitudinal travel slots 44 that are formed in the track beams 12, opposite end extremities of the travel slots defining travel limits between the retracted and extended conditions of the wheel slide 10.

In the exemplary configuration shown in the drawings, the roller slide 10 has five pairs of the wheels 16, the axles 18 being individually spaced apart by a distance S for an overall wheelbase of 4 S, each of the track beams 12 and the center beam 14 being of uniform overall length L. Each of the travel slots 44 is of sufficient length to allow relative travel of the axle 18′ for a distance D being 2 S, the slide 10 being capable of an extension distance E, which in this case is 2 D or 4 S. In a prototype roller slide 10 in this configuration, the length L is 610 mm and the distance S is 125 mm, the axle 18′ being centrally located on the center beam 14. Thus the overall wheelbase 4 S is 500 mm, the extension distance E being 500 mm. In this case, the extension distance E is 82 percent of the length L. Also, each of the track beams 12 is engaged by wheels 16 that are spaced apart by the distance D (250 mm being 41 percent of the length L) when the slide 10 is in the fully extended condition, and 2 D or 82 percent in the retracted position. In intermediate conditions wherein one only of the wheels 16 runs beyond engagement with a corresponding track beam, that track beam has wheel engagement at a spacing of 3 S (375 mm) or more than 60 percent of the length L. In this prototype configuration the wheels 16 have a diameter W of 36 mm, the wheels thus being confined within the length L such that the slide assembly 10 also has the same overall length in the retracted condition. It will be understood that the same overall length is obtained when 4 S+W≦L, so that S can be increased to (L−W)/4, which for L=610 mm and W=36 mm is 143.5 mm, whereby the extension distance E becomes 574 mm, or more than 94 percent of L. It will be further understood that while other combinations of dimensions will alter the relative extension distances and spacings of wheel engagement with the track surfaces, it is apparent that roller slides according to the present invention can provide wheel engagement at a spacing of not less than 60 percent of a track length of that track beam in a first (retracted) relative longitudinal position of the track beams and not less than 30 percent of the track length in a second (extended) position of the track beams, an extension distance between the first and second positions being not less than 80 percent of the track length. Also, since the guide flanges 26 and the guide slots 28 are uniformly formed for the full lengths of the track beams 12 and the center beam 14, the guide flanges engage the guide slots at locations spaced apart on each track beam not less than half of the corresponding track length.

In further details of the prototype roller slide assembly 10, each track beam 12 has a section height H of 42 mm, the beam main portion 20 having a width A of 14mm, the track surface having a width K of 6 mm, the mounting flange portion 22 projecting 15 mm for an overall track beam width B of 29 mm. The track beams 12 are spaced apart by only 1 mm, the assembly 10 having an overall width C of 59 mm. The center beam 14 has a section height F of 33 mm, a width G of 20.5 mm, and a section thickness T of 1.5 mm, the lateral webs 32 being vertically spaced by a distance M of 20 mm.

Suitable materials for the track beams 12 and the center beam 14 include high-strength aluminum extrusions. Suitable materials for the wheels 16 include acetyl resins and other rigid polymers.

As shown in FIGS. 9 and 10, the roller slide assembly 10 of the present invention is particularly suitable for use as a table extension slide. A table 50 having a pair of main leaves 52 with respective leg pedestals 54 attached thereto for support thereof, has a laterally spaced pair of roller slide assemblies 10 connecting the main leaves 52 as described herein. The slide assemblies are preferably oppositely handed for symmetry, being designated 10R and 10L in FIGS. 9 and 10. Each of the slide assemblies 10 has one track beam 12 thereof attached to one of the main leaves 52 using suitable fasteners (not shown) located at respective ones of the mounting holes 39, the other track beam being similarly attached to the other main leaf 52, with the main leaves in edgewise contact in the retracted condition of the slide assemblies 10 as shown in FIG. 9. For this use of the present invention, the mounting holes 39 are appropriately located lengthwise opposite the travel slot 44 from the central axle 18′ as shown in FIG. 1. FIG. 10 shows the table 50 with the roller slide assemblies 10 in the extended condition, the main leaves being separated by the extension distance E for receiving one or more auxiliary leaves (not shown).

With further reference to FIG. 11, an alternative configuration of the roller slide assembly, designated 10′, includes counterparts of the wheels, designated 16′, having cushioned engagement with the track surfaces 24 of the track beams 12. More particularly, each wheel 16′ includes a ring-shaped tire 56 that is recessed at an outer periphery of a wheel 58, each pair of the wheels 16′ being rotatably supported by a counterpart of the axle 18 as described above. The tire 56 can be a rubber O-ring. Alternatively, the tire can be a resilient coating that is applied to the

Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. For example, the wheels 16 of each pair can be made as a single wide wheel notwithstanding the described separate wheels being preferred for enhanced freedom of axial movement. Also, other wheel arrangements are contemplated, including three pairs thereof wherein the axle spacing can match the travel distance D. When objects to which the slide assembly are connected can pass each other, the slot 44 can be extended in opposite directions from the central axle 18′, the extension distance E being effectively doubled by projecting from opposite ends of the assembly in its retracted condition. Therefore, the spirit and scope of the appended claims should not necessarily be limited to the description of the preferred versions contained herein. 

1. A roller extension apparatus comprising: (a) elongate first and second track beams, each track beam having parallel-spaced facing track surfaces; (b) an elongate center beam; (c) a longitudinally spaced plurality of wheels rotatably mounted on the center beam for rolling engagement with the track surfaces of the first and second track beams; and (d) means for maintaining the parallel spaced relation of the track beams, wherein each of the track beams has track beam wheel engagement at a spacing of not less than 60 percent of a track length of that track beam in a first relative longitudinal position of the track beams and not less than 30 percent of the track length in a second position of the track beams, an extension distance between the first and second positions being not less than 80 percent of the track length.
 2. The apparatus of claim 1, further comprising means for limiting travel of the rolling engagement between the relative longitudinal first and second positions of the track beams.
 3. The apparatus of claim 2, wherein the means for limiting travel comprises a longitudinal travel slot being formed in each track beam, and respective wheel axle extensions projecting from the center beam engaging opposite ends of the travel slots.
 4. The apparatus of claim 1, wherein the track beams and the center beam are of equal length, the first relative position being with the apparatus substantially contained within the track length.
 5. The apparatus of claim 1, wherein the means for maintaining the parallel spaced relation of the track beams comprises: (a) each track beam having a longitudinal guide slot formed therein; and (b) the center beam having a plurality of guide flanges for slidably engaging the guide slots of corresponding track beams.
 6. The apparatus of claim 5, wherein each of the guide flanges is one of an oppositely facing pair of flange portions, and the guide slot of each track member is one of a facing pair of guide slots.
 7. The apparatus of claim 6, wherein the guide flanges engage the guide slots at locations spaced apart on each track beam not less than half of the corresponding track length.
 8. The apparatus of claim 6, wherein the center beam comprises a main portion having a pair of parallel-spaced side webs connected by parallel-spaced lateral webs, the wheels being mounted between the side webs and projecting through clearance openings formed in the lateral webs, the oppositely extending guide flanges being coplanar extensions of the side webs.
 9. The apparatus of claim 1, wherein each track beam comprises a main portion of generally C-shaped cross-section including a pair of parallel-spaced track flanges forming the track surfaces, and a connecting web.
 10. The apparatus of claim 9, each track beam further comprising a mounting flange extending from the connecting web opposite one of the track flanges in generally coplanar relation thereto.
 11. The apparatus of claim 1, further comprising a longitudinally spaced plurality of axles mounted to the center beam, each axle supporting an independently rotatable pair of the wheels, each of the wheels being located between the track surfaces of a corresponding one of the track beams.
 12. The apparatus of claim 11, wherein the axles are mounted proximate opposite ends thereof to the center beam.
 13. The apparatus of claim 1, wherein at least some of the wheels comprise an outer resilient member for cushioned contact with the track surfaces of the track beam.
 14. The apparatus of claim 13, wherein the outer resilient member is a rubber )-ring.
 15. A table comprising the apparatus of claim 1 in combination with a first panel member being mounted to the first track beam and a second panel member mounted to the second track beam in coplanar relation to the first article, the articles being in edgewise proximity in the first relative position of the track beams and being spaced apart in the second relative position of the track beams.
 16. The apparatus of claim 15, comprising a parallel spaced pair of the apparatus of claim 1 correspondingly connected between the first and second panel members.
 17. A roller extension apparatus comprising: (a) elongate first and second track beams, each track beam having parallel-spaced facing track surfaces and comprising a main portion of generally C-shaped cross-section including a pair of parallel-spaced track flanges forming the track surfaces, and a connecting web; (b) an elongate center beam comprising a pair of parallel-spaced side webs connected by parallel-spaced lateral webs; (c) a longitudinally spaced plurality of wheels rotatably mounted between the side webs and projecting through clearance openings formed in the lateral webs of the center beam for rolling engagement with the track surfaces of the first and second track beams; (d) means for maintaining the track beams in a predetermined parallel-spaced relation during the rolling engagement, comprising: (i) each track beam having a longitudinal guide slot formed therein; and (ii) the center beam having a plurality of guide flanges for slidably engaging the guide slots of corresponding track beams; and (e) means for limiting travel of the rolling engagement between the relative longitudinal first and second positions of the track beams, comprising a longitudinal travel slot being formed in each track beam, and respective wheel axle extensions projecting from the center beam engaging opposite ends of the travel slots, wherein each of the track beams has track beam engagement at a spacing of not less than 80 percent of a track length of that track beam in a first relative longitudinal position of the track beams and not less than 40 percent of the track length in a second position of the track beams, an extension distance between the first and second positions being not less than 80 percent of the track length, and wherein the track beams and the center beam are of equal length, the first relative position being with the apparatus substantially contained within the track length.
 18. The apparatus of claim 17, wherein each of the guide flanges is one of an oppositely facing pair of flange portions, and the guide slot of each track member is one of a facing pair of guide slots, and the oppositely extending guide flanges are coplanar extensions of the side webs of the center beam. 